The present invention pertains to repositioning articles within a space that is accessible for said repositioning only during a series of periods that are separated by intervals of less accessibility for said repositioning than during said periods.
For various manufacturing and other processes it is desirable to reposition an article within a given space between processing steps. When an article has to be moved from a first processing position within the given space to a second processing position within the given space, but such movement is impeded or made impossible by changes in the accessibility of the given space for said repositioning that are necessitated by one or more aspects of the process, such repositioning typically is carried out during those periods when the given space is more accessible for said repositioning but not during those intervals when the given space is less accessible for repositioning. As a result, such accessible periods may be of such an extended duration as to slow down or halt the overall process and thereby make the overall process less efficient.
For example, in a process for injection molding a multi-component product a first component formed in a first mold cavity by injection molding is repositioned to a second mold cavity in which a second component of the product is formed in combination with the first component by injection molding the second component. Such repositioning within the space between the mold parts can be accomplished only during a period of time when the mold is open, and typically is accomplished by means of a robot arm that (a) attaches onto the first component in the first mold-cavity position with an attachment mechanism on the robot arm, (b) moves the attached first component from the first mold-cavity position to a second mold-cavity position and (c) releases the first component from the attachment mechanism. However, the time required for attaching onto the first component, moving the attached first component from the first mold-cavity position to the second mold-cavity position and releasing the first component is greater than the time required for merely attaching onto a molded article and moving the attached molded article from its mold-cavity position when repositioning of the molded article is not required, whereby such repositioning from the first mold-cavity position to the second mold-cavity position within the space between the mold parts makes it necessary to keep the mold open for a longer period of the time so that the space between the mold parts will be accessible until said repositioning is completed.
In one aspect, the present invention provides a method of repositioning articles within a space that is accessible for said repositioning only during a series of periods that are separated by intervals of less accessibility for said repositioning, comprising the steps of:
(a) during a first said period, moving a first article from a first position within said space to outside of said space; and
(b) during the first period, moving a second article from outside of said space to a second position within said space;
wherein said movement of the first article and said movement of the second article are by means of a common vehicle.
By using the same means, such as a common vehicle, to move the second article from outside of said space to the second position and then move the first article from the first position within said space to outside of said space during the same period of accessibility, the combined time required for repositioning both articles is reduced significantly and a separate repositioning step that would be required if both the movement of the second article to the second position and the movement of the first article from the second position were not accomplished by same means is eliminated.
In another aspect, the present invention provides a method of repositioning articles within a space that is accessible for said repositioning only during a series of periods that are separated by intervals of less accessibility for said repositioning, comprising the steps of:
(a) during a first said period, moving a first article from a first position within said space to outside of said space; and
(b) during the first period, moving an identical second article from outside of said space to a second position within said space.
In a further aspect, the present invention provides a method of repositioning articles within a space that is accessible for said repositioning only during a series of periods that are separated by intervals of less accessibility for said repositioning than during said periods, comprising the steps of:
(a) during a first said period, moving a first article from a first position within said space to outside of said space; and
(b) during a second said period after a said interval of less accessibility that is subsequent to the first period, moving the first article from outside of said space to a second position within said space.
Accordingly, the repositioning method of the present invention does not require that the space be accessible for a period of time greater than the time required for attaching onto a first article and moving the attached first article from the first position within said space, whereby such repositioning method decreases the time during which the space must be accessible for said repositioning in relation to the accessible time required in the prior art repositioning method described above. Preferably, the first period is separated from the second period by only one interval of less accessibility.
The repositioning methods of the present invention are particularly applicable for repositioning articles within a space between mold parts that defme a plurality of mold cavities when the mold is closed, wherein said space is accessible for said repositioning only during a series of open-mold periods that are separated by closed-mold intervals of inaccessibility for said repositioning.
Additional features of the present invention are described with reference to the detailed description of the preferred embodiments.